Scorer vs metrics/test cases

[mausch]

Hi, I'm new to deepeval, currently evaluating it.
One thing I find puzzling is the API divide between e.g. https://docs.confident-ai.com/docs/metrics-hallucination and Scorer.hallucination_score
I get that one uses an LLM and the other one doesn't, but it's pretty confusing to have these two wildly different APIs? Is there a reason for this?